Telecontrol system

Abstract

A telecontrol system is disclosed whose substations contain a control unit and plug-in interface modules for entering messages or measured values and delivering commands. Both the control unit and the interface modules are equipped with microcomputers and connected via suitable interfaces to a common serial data bus. Because of the presence of the serial data bus, the parallel buses of the microcomputers need not leave the individual modules, which reduces the susceptibility to interference on the buses. In addition, the serial data bus makes it possible to use any form of protection coding, so that individual modules can even be located away from the substation. Each interface module consists of an invariant portion, which is of the same design in all modules, and a problem-adapted portion, whose design depends on the task to be performed.

We claim: 
     
       1. A telecontrol system with at least one master station and a plurality of substations connected to the master station via data transmission units, each substation containing a control unit equipped with a microcomputer and a plurality of plug-in interface modules connected to the control unit and serving to enter messages and measured values and to deliver commands, wherein said interface modules are equipped with microcomputers, and that both the control unit and all interface modules of a substation have interfaces to, and are interconnected by, a serial data bus permitting the use of protection coding techniques wherein each interface module has a first subcircuit which includes said microcomputer, and is coupled to said control unit by a serial data bus over which said interface module is cyclically scanned for temporarily stored messages; and a second subcircuit for providing isolation between said interface module and a facility to be monitored, and wherein said first subcircuits in all interface modules are of the same design and contain, besides the microcomputer with main memory and program memory and the interface to the serial data bus, a function-code memory in which the function of the respective interface module can be fixed by coding, and wherein said second subcircuit includes all components necessary for adaptation to the technical facility to be monitored and controlled. 
     
     
       2. A telecontrol system as claimed in claim 1 characterized in that the master station and the control units of the substations have interface-module registers in which the function code of all inserted interface modules and an address assigned to the socket used are stored. 
     
     
       3. A telecontrol system as claimed in claim 2, characterized in that the interface modules have disabling devices each of which is connected to and controllable from an adjacent interface module.